dropbear: random.c annotate

annotate random.c @ 708:b207d5183bb7

document a few more changes

author	Matt Johnston <matt@ucc.asn.au>
date	Wed, 20 Mar 2013 00:05:19 +0800
parents	48e173a0c52b
children	84157e435c52

rev	line source
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	1 /*
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	2 * Dropbear - a SSH2 server
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	3 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	4 * Copyright (c) 2002,2003 Matt Johnston
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	5 * All rights reserved.
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	6 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	7 * Permission is hereby granted, free of charge, to any person obtaining a copy
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	8 * of this software and associated documentation files (the "Software"), to deal
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	9 * in the Software without restriction, including without limitation the rights
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	11 * copies of the Software, and to permit persons to whom the Software is
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	12 * furnished to do so, subject to the following conditions:
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	13 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	14 * The above copyright notice and this permission notice shall be included in
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	15 * all copies or substantial portions of the Software.
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	16 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	23 * SOFTWARE. */
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	24
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	25 #include "includes.h"
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	26 #include "buffer.h"
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	27 #include "dbutil.h"
188 c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	28 #include "bignum.h"
698 5f2d16d3e598 fix signedness error in prototype Matt Johnston <matt@ucc.asn.au> parents: 694 diff changeset	29 #include "random.h"
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	30
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	31 /* this is used to generate unique output from the same hashpool */
272 3be7ae2e8dfa Only read /dev/random once when the program starts Matt Johnston <matt@ucc.asn.au> parents: 198 diff changeset	32 static uint32_t counter = 0;
298 7dad470ad4aa minor cleanups for some warnings Matt Johnston <matt@ucc.asn.au> parents: 272 diff changeset	33 /* the max value for the counter, so it won't integer overflow */
7dad470ad4aa minor cleanups for some warnings Matt Johnston <matt@ucc.asn.au> parents: 272 diff changeset	34 #define MAX_COUNTER 1<<30
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	35
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	36 static unsigned char hashpool[SHA1_HASH_SIZE] = {0};
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	37 static int donerandinit = 0;
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	38
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	39 #define INIT_SEED_SIZE 32 /* 256 bits */
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	40
149 ed9ca2a9705c Cleaned up the random code, use /dev/random by default, Matt Johnston <matt@ucc.asn.au> parents: 70 diff changeset	41 /* The basic setup is we read some data from /dev/(u)random or prngd and hash it
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	42 * into hashpool. To read data, we hash together current hashpool contents,
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	43 * and a counter. We feed more data in by hashing the current pool and new
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	44 * data into the pool.
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	45 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	46 * It is important to ensure that counter doesn't wrap around before we
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	47 * feed in new entropy.
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	48 *
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	49 */
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	50
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	51 /* Pass len=0 to hash an entire file */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	52 static int
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	53 process_file(hash_state hs, const char filename,
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	54 unsigned int len, int prngd)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	55 {
185 5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	56 static int already_blocked = 0;
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	57 int readfd;
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	58 unsigned int readcount;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	59 int ret = DROPBEAR_FAILURE;
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	60
149 ed9ca2a9705c Cleaned up the random code, use /dev/random by default, Matt Johnston <matt@ucc.asn.au> parents: 70 diff changeset	61 #ifdef DROPBEAR_PRNGD_SOCKET
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	62 if (prngd)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	63 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	64 readfd = connect_unix(filename);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	65 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	66 else
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	67 #endif
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	68 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	69 readfd = open(filename, O_RDONLY);
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	70 }
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	71
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	72 if (readfd < 0) {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	73 goto out;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	74 }
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	75
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	76 readcount = 0;
694 c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	77 while (len == 0 \|\| readcount < len)
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	78 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	79 int readlen, wantread;
694 c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	80 unsigned char readbuf[2048];
185 5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	81 if (!already_blocked)
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	82 {
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	83 int ret;
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	84 struct timeval timeout = { .tv_sec = 2, .tv_usec = 0};
185 5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	85 fd_set read_fds;
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	86
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	87 FD_ZERO(&read_fds);
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	88 FD_SET(readfd, &read_fds);
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	89 ret = select(readfd + 1, &read_fds, NULL, NULL, &timeout);
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	90 if (ret == 0)
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	91 {
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	92 dropbear_log(LOG_WARNING, "Warning: Reading the randomness source '%s' seems to have blocked.\nYou may need to find a better entropy source.", filename);
185 5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	93 already_blocked = 1;
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	94 }
5ccad7634388 * warn if we seem to be blocking on /dev/random Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	95 }
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	96
694 c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	97 if (len == 0)
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	98 {
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	99 wantread = sizeof(readbuf);
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	100 }
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	101 else
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	102 {
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	103 wantread = MIN(sizeof(readbuf), len-readcount);
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	104 }
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	105
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	106 #ifdef DROPBEAR_PRNGD_SOCKET
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	107 if (prngd)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	108 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	109 char egdcmd[2];
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	110 egdcmd[0] = 0x02; /* blocking read */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	111 egdcmd[1] = (unsigned char)wantread;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	112 if (write(readfd, egdcmd, 2) < 0)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	113 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	114 dropbear_exit("Can't send command to egd");
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	115 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	116 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	117 #endif
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	118
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	119 readlen = read(readfd, readbuf, wantread);
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	120 if (readlen <= 0) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	121 if (readlen < 0 && errno == EINTR) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	122 continue;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	123 }
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	124 if (readlen == 0 && len == 0)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	125 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	126 /* whole file was read as requested */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	127 break;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	128 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	129 goto out;
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	130 }
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	131 sha1_process(hs, readbuf, readlen);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	132 readcount += readlen;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	133 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	134 ret = DROPBEAR_SUCCESS;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	135 out:
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	136 close(readfd);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	137 return ret;
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	138 }
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	139
698 5f2d16d3e598 fix signedness error in prototype Matt Johnston <matt@ucc.asn.au> parents: 694 diff changeset	140 void addrandom(char * buf, unsigned int len)
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	141 {
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	142 hash_state hs;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	143
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	144 /* hash in the new seed data */
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	145 sha1_init(&hs);
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	146 /* existing state (zeroes on startup) */
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	147 sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	148
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	149 /* new */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	150 sha1_process(&hs, buf, len);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	151 sha1_done(&hs, hashpool);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	152 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	153
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	154 static void write_urandom()
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	155 {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	156 #ifndef DROPBEAR_PRNGD_SOCKET
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	157 /* This is opportunistic, don't worry about failure */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	158 unsigned char buf[INIT_SEED_SIZE];
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	159 FILE *f = fopen(DROPBEAR_URANDOM_DEV, "w");
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	160 genrandom(buf, sizeof(buf));
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	161 fwrite(buf, sizeof(buf), 1, f);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	162 fclose(f);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	163 #endif
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	164 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	165
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	166 /* Initialise the prng from /dev/urandom or prngd. This function can
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	167 * be called multiple times */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	168 void seedrandom() {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	169
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	170 hash_state hs;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	171
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	172 pid_t pid;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	173 struct timeval tv;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	174 clock_t clockval;
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	175
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	176 /* hash in the new seed data */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	177 sha1_init(&hs);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	178 /* existing state */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	179 sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	180
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	181 #ifdef DROPBEAR_PRNGD_SOCKET
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	182 if (process_file(&hs, DROPBEAR_PRNGD_SOCKET, INIT_SEED_SIZE, 1)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	183 != DROPBEAR_SUCCESS) {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	184 dropbear_exit("Failure reading random device %s",
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	185 DROPBEAR_PRNGD_SOCKET);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	186 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	187 #else
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	188 /* non-blocking random source (probably /dev/urandom) */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	189 if (process_file(&hs, DROPBEAR_URANDOM_DEV, INIT_SEED_SIZE, 0)
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	190 != DROPBEAR_SUCCESS) {
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	191 dropbear_exit("Failure reading random device %s",
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	192 DROPBEAR_URANDOM_DEV);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	193 }
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	194 #endif
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	195
694 c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	196 /* A few other sources to fall back on.
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	197 * Add more here for other platforms */
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	198 #ifdef __linux__
688 650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	199 /* Seems to be a reasonable source of entropy from timers. Possibly hard
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	200 * for even local attackers to reproduce */
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	201 process_file(&hs, "/proc/timer_list", 0, 0);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	202 /* Might help on systems with wireless */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	203 process_file(&hs, "/proc/interrupts", 0, 0);
688 650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	204
694 c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	205 process_file(&hs, "/proc/loadavg", 0, 0);
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	206 process_file(&hs, "/proc/sys/kernel/random/entropy_avail", 0, 0);
c85bb68e1db6 add loadavg and entropy_avail as sources Matt Johnston <matt@ucc.asn.au> parents: 689 diff changeset	207
688 650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	208 /* Mostly network visible but useful in some situations */
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	209 process_file(&hs, "/proc/net/netstat", 0, 0);
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	210 process_file(&hs, "/proc/net/dev", 0, 0);
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	211 process_file(&hs, "/proc/net/tcp", 0, 0);
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	212 /* Also includes interface lo */
650c41a4909a Add a few more files in /proc for Linux Matt Johnston <matt@ucc.asn.au> parents: 687 diff changeset	213 process_file(&hs, "/proc/net/rt_cache", 0, 0);
702 48e173a0c52b Include /proc/vmstat as another random source Matt Johnston <matt@ucc.asn.au> parents: 698 diff changeset	214 process_file(&hs, "/proc/vmstat", 0, 0);
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	215 #endif
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	216
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	217 pid = getpid();
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	218 sha1_process(&hs, (void*)&pid, sizeof(pid));
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	219
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	220 gettimeofday(&tv, NULL);
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	221 sha1_process(&hs, (void*)&tv, sizeof(tv));
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	222
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	223 clockval = clock();
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	224 sha1_process(&hs, (void*)&clockval, sizeof(clockval));
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	225
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	226 /* When a private key is read by the client or server it will
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	227 * be added to the hashpool - see runopts.c */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	228
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	229 sha1_done(&hs, hashpool);
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	230
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	231 counter = 0;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	232 donerandinit = 1;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	233
687 167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	234 /* Feed it all back into /dev/urandom - this might help if Dropbear
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	235 * is running from inetd and gets new state each time */
167fdc091c05 Improve RNG seeding. Matt Johnston <matt@ucc.asn.au> parents: 602 diff changeset	236 write_urandom();
272 3be7ae2e8dfa Only read /dev/random once when the program starts Matt Johnston <matt@ucc.asn.au> parents: 198 diff changeset	237 }
3be7ae2e8dfa Only read /dev/random once when the program starts Matt Johnston <matt@ucc.asn.au> parents: 198 diff changeset	238
4 fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	239 /* return len bytes of pseudo-random data */
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	240 void genrandom(unsigned char* buf, unsigned int len) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	241
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	242 hash_state hs;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	243 unsigned char hash[SHA1_HASH_SIZE];
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	244 unsigned int copylen;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	245
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	246 if (!donerandinit) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	247 dropbear_exit("seedrandom not done");
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	248 }
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	249
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	250 while (len > 0) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	251 sha1_init(&hs);
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	252 sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	253 sha1_process(&hs, (void*)&counter, sizeof(counter));
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	254 sha1_done(&hs, hash);
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	255
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	256 counter++;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	257 if (counter > MAX_COUNTER) {
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	258 seedrandom();
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	259 }
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	260
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	261 copylen = MIN(len, SHA1_HASH_SIZE);
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	262 memcpy(buf, hash, copylen);
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	263 len -= copylen;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	264 buf += copylen;
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	265 }
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	266 m_burn(hash, sizeof(hash));
fe6bca95afa7 Makefile.in contains updated files required Matt Johnston <matt@ucc.asn.au> parents: diff changeset	267 }
188 c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	268
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	269 /* Generates a random mp_int.
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	270 * max is a *mp_int specifying an upper bound.
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	271 * rand must be an initialised *mp_int for the result.
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	272 * the result rand satisfies: 0 < rand < max
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	273 * */
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	274 void gen_random_mpint(mp_int max, mp_int rand) {
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	275
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	276 unsigned char *randbuf = NULL;
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	277 unsigned int len = 0;
433 c216212001fc Fix for -pedantic -ansi compilation, change // to /*/, plus some signedness Matt Johnston <matt@ucc.asn.au>* parents: 405 diff changeset	278 const unsigned char masks[] = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
188 c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	279
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	280 const int size_bits = mp_count_bits(max);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	281
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	282 len = size_bits / 8;
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	283 if ((size_bits % 8) != 0) {
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	284 len += 1;
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	285 }
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	286
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	287 randbuf = (unsigned char*)m_malloc(len);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	288 do {
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	289 genrandom(randbuf, len);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	290 /* Mask out the unrequired bits - mp_read_unsigned_bin expects
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	291 * MSB first.*/
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	292 randbuf[0] &= masks[size_bits % 8];
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	293
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	294 bytes_to_mp(rand, randbuf, len);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	295
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	296 /* keep regenerating until we get one satisfying
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	297 * 0 < rand < max */
405 00703f1df67a Remove extraneous tests in random mpint generation, Matt Johnston <matt@ucc.asn.au> parents: 311 diff changeset	298 } while (mp_cmp(rand, max) != MP_LT);
188 c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	299 m_burn(randbuf, len);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	300 m_free(randbuf);
c9483550701b - refactored random mp_int generation and byte->mp_int code Matt Johnston <matt@ucc.asn.au> parents: 159 diff changeset	301 }

Mercurial > dropbear

annotate random.c @ 708:b207d5183bb7